package org.bouncycastle.asn1.x9;

import org.bouncycastle.asn1.ASN1Choice;
import org.bouncycastle.asn1.ASN1Encodable;
import org.bouncycastle.asn1.ASN1Null;
import org.bouncycastle.asn1.ASN1TaggedObject;
import org.bouncycastle.asn1.DERObject;
import org.bouncycastle.asn1.DERObjectIdentifier;

public class X962Parameters extends ASN1Encodable implements ASN1Choice {
    private DERObject params = null;

    public static X962Parameters getInstance(Object obj) {
        if (obj == null || obj instanceof X962Parameters) {
            return (X962Parameters) obj;
        }

        if (obj instanceof DERObject) {
            return new X962Parameters((DERObject) obj);
        }

        throw new IllegalArgumentException("unknown object in getInstance()");
    }

    public static X962Parameters getInstance(ASN1TaggedObject obj,
            boolean explicit) {
        return getInstance(obj.getObject()); // must be explicitly tagged
    }

    public X962Parameters(X9ECParameters ecParameters) {
        this.params = ecParameters.getDERObject();
    }

    public X962Parameters(DERObjectIdentifier namedCurve) {
        this.params = namedCurve;
    }

    public X962Parameters(DERObject obj) {
        this.params = obj;
    }

    public boolean isNamedCurve() {
        return (params instanceof DERObjectIdentifier);
    }

    public boolean isImplicitlyCA() {
        return (params instanceof ASN1Null);
    }

    public DERObject getParameters() {
        return params;
    }

    /**
     * Produce an object suitable for an ASN1OutputStream.
     * 
     * <pre>
     * Parameters ::= CHOICE {
     *    ecParameters ECParameters,
     *    namedCurve   CURVES.&id({CurveNames}),
     *    implicitlyCA NULL
     * }
     * </pre>
     */
    public DERObject toASN1Object() {
        return params;
    }
}
